Sea surface temperature anomalies (SSTA) in the Eastern Pacific, specifically off the Peruvian coast, have shown a recent warming. SSTA is defined as the difference between the actual temperature and normal conditions for that time of year. Negative anomalies indicate cooler than normal temperatures, while positive anomalies indicate warmer than normal temperatures. Warm anomalies greater than 2°C have been persistent off the northern to central coast of Peru for over one month. Such warming events off Peru have been historically known to precede El Niño conditions in the Equatorial Pacific.  Although it is too early to determine whether such warm anomalies will lead to a shift to El Niño conditions in the Equatorial Pacific, some local effects have already been seen.

Effects of this warming on the biology are already being observed.  Hundreds of birds and dolphins have been washing up dead along the Peruvian coast. However, such deaths have been previously reported during the 1997-98 El Niño. Although it is impossible to determine whether a 2012 El Niño is coming or how strong it would be, the coupling between ocean temperatures and the biology continues to have far reaching consequences that can severely affect coastal regions such as Peru.